Transforming device.



T. BODDE.

TRANSFORMING DEVICE.

APPLICATION man APR-13.1918.

Fig. 2.

Permeability 6 M W O n MW AG Theod STATES PATENT o FIoE.

THEODORE BOIODE, OF LY N N, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TRANSFORMING DEVTGE.

To all whom it mag concern:

Be it known that I, THEODORE Bojnnn, a

' subject of the Queen of the Netherlands, re-

siding at Lynn, in the county of Essex, State of Massachusetts, have invented certain new and useful Improvements inTransforming Devices, of which the following is a specification.

My invention relates to transforming devices fof supplying constant current from constant potential sources; more particularly my 'invention relates to s'ta tionary' transformers and rectifier-s for sup-plying'direct currents of constant values from alternating current sources of constant potentials. It includes both a method of operation and a particular form of apparatus opcrating according to that method- An object of'my invention is to obtain such constant currents without the employment of. devices having moving parts. y

Apparatus in which my invention is employed comprises a stationary transformer in which the flux common to or threading both the primary and secondary windings is varied in proportion to the load variations by varying the permeability of a magnetic circuit of said transformer. To obtain rectified constant current two opposing direct current coils, respectively in shunt to and in series with the direct current side of the rectifier, may be used to control the permeability of a magnetic shunt or othersuitable circuit on said transformer.

. In the accompanying drawings I have illustrated one form of apparatus embodying my invention and which operates according to the method thereof. Figure l diagrammatically illustrates a stationary transformer supplying direct current of constant value to a load through a mercury rectifier; Fig. 2 is a permeability curve of as sistance in understanding the operation of the apparatus of Fig. 1.

In Fig. 1 the transformer l com-prises the core 2 carrying the windings; the primary winding 3 receives alternating current from the lines 1 and supplies the energy for the rectifier and load. The core 2 provides a magnetic circuit 5 common to the primary winding 3 and the secondary winding which is in two portions 7 and 8. The two secondary windings 7 and 8 in series supply the rectifier 15 which may be of any type. The core 2 also provides a magnetic shunt 10 for -windings 12 and 13. winding 12is connected in series with the the primary and secondary windings. Between Patented Mar. 25, 1919. Application filed April 13, 1916. 'Serial No. 90,856.

a mid-pointzof this magnetic shunt and the portion of the core between the secondary windings 7 and 8 is provided a part or member 11, also of magnetic material. This part or member 11 carries two direct current The direct. current load 16. The direct current winding 13-is connected in shunt to the rectifier and secondary windings 7 and 8. It is connected as shown in the drawings, between the midpoint connection of the rectifier and the midpoint of the secondary windings 78. The current carried by the direct current winding 12-therefbre is proportional to the current supplied to the load, whereas the current supplied to the direct current winding -13 is proportional to the direct voltage impressedon the load. The two windings 12 and 13 'ar'eso wound or connected that their magnetic actions oppose each other, the voltage coil 13 predominating. V

The lines carrying the arrows indicate the courses of the magnetic fluxes through the core. At some certain instant the magnetic flux common to or linking both the primary and secondary windings may be represented by the line and arrows 18'. The alternating current leakage flux at the same instant is indicated by the line and arrows I 19. The direct current flux resulting from the predominance of the voltage coil 13 passes through the member 11 and shunt 10 as indicated by the, lines and arrows 20. It will be observed that the shunt 10 is traversed both by the leakage alternating flux and by the direct flux; it will also be observed that the direct current coils 12 and 13 are not subject to alternating flux andthis load and irrespective of variations in i the voltage of the alternating current supply 4. It will be understood that although the alternating current supply 4 is of the socalled constant potential type as before indi-' cated, the voltage of this source may be subject to more or less abrupt and continued voltage changes within 'limits, due to the operation of other devices connected to the same source 4; or for other reasons; and also that the voltage of the source 4 may be found when the apparatus is installed, to be some" what different from the voltage contemplated in the design of the apparatus. Now

spondingly lower value. These tendencies of the load current to change, by their efiects on the magnetic flux result in-the regulation desired. As will be observed. from Fig. 2,

and as is well known, the permeability of magnetic material as iron or steel, varies considerably with the flux density; it will be assumed that the permeability of the shunt 10 is represented by this curve, the flux density represented being the .total flux density of the magnetic shunt 10, the com bination of the alternating and direct fluxes therein. The apparatusof Fig. 1 may be so designed that at full load the flux density of the shunt 10 is of the value of the point 30 of Fig. 2. The permeability of the shunt 10 is' then low and of the value represented by the point 31' on the permeability curve; the value of certain leakage alternating flux,

and therewith the flux common to the pri my invention and the best mode I have contemplated for applying this principle, other mary and secondary windings, is determined by the permeability of the shunt 1'0, and hence is influenced by the direct current coils 12 and 13 and their direct flux. If now some of the devices of the series load 16. are removed from the circuit or if for any other reason the current tends to increase, the

' voltage impressed on the load should fall to a corresponding extent in order that the current may be maintained at its original value. This result is obtained by decreasing the flux common to-the primary and secondary windings proportionally to the change in load or other change, as change in the voltage of the source, by increasing the permeability of the magnetic shunt 10 and hence providing for the passage therethrough of v a greater value of leakage flux. The complete action is complicated and involves the super 0s1t1on of the alternating and the'direct uxes' The action may be sufficiently understood, however, from a consideration of the action of the direct currents and fluxes. For example, as the current tends to increase as'some of the load devices 16 are taken from the circuit, the direct current series winding 12 lands to more strongly oppose'the voltage coil 13 and hence reduce the dlrect flux; this accomplishes the increase 1n permeability of the shunt 10 as will be apparent from Fig. 2. This increase in permeabil ty in the shunt l0 isaccompanied current toward its original value so t0v speak. .At some value ofload voltage, the

effects of this'voltage and the load current in the direct current coils 12 and 13 againbalance each other, any further tendency of the current to change being opposed by a corresponding change in voltage in the opposite direction. Thus, after a given decrease in load the flux density in the shunt 10 may be of the value of the point 32 of Fig. 2, the permeability of the shunt having been increased to the value of the point 33.

By properly proportioning the two direct/ current windings 12 and 13 the change in total flux density and permeability in the shunt lO-is madesuch that the current supvalue for all values of load. If later the load is increased again to something more nearly full load value, the opposite action takes place as will be understood.

' plied to the load has substantially the same While I have described the principle of modifications will occur to those skilled in this art and'I aiminthe appended claims to cover all modifications which do not in-' volve a departure from the spirit and scope of my invention.

What I claim as new and. desire to secure by Letters Patent of the United States, is

1. The method of producing a current of constantvalue from a .constant potential alterating current by means of a stationary transformer having a core provided with a stationary magnetic shunt which consists in dividing the primary magnetic flux into two portions one threading the secondary windings, the other threading the magnetic shunt, and in changing the permeability of the magnetic shunt in substantially inverse proportion to changes in the load resistance.

2. The method of producing a direct current of constant value from a constant potential alternating current by means of a stationary transformer and a rectifier which consists in supplying the rectifier from the secondary winding of the transformer and varying the flux common'to the primary and secondary windings proportional to the load variations by varying the permeability of a magnetic circuit of said stationary transformer by the opposing-actions of the rectifiedcurrent and rectified voltage.

means 3. The combination with a rectifier and means for supplying alternating current,

.of a transformer comprising a primary winding connected to said means, a secondary winding supplying said rectifier, two opposing windings connected respectively in shunt to and in series with the load terminals of said devices, and a core of magnetic materiarproviding a common magnetic circuit for said primary and secondary windings, a magnetic shunt therefor and a member carryin said two direct current windings extending between a midpoint of said magnetic shunt and a point on said first mentioned magnetic circuit at the middle of one of said alternating current windings.

4:. The combination with a constant tential source of alternating current, 0? a transformer comprising a magnetic core, primary and secondary windings carried thereby, said core being provided with a stationary magnetic shunt, and series and shunt windings 011 said core arranged for magnetically changing the permeability of said magnetic shunt in substantially inverse proportion to changes in the load resistance.

5. The combination with a constant 0- tential source of alternating current, of a transformer comprising a magnetic core, primary thereby, said core being provided with a stationary magnetic shunt, and means energized by the load current for magnetically changing the permeability of said magnetic and secondary win'dings carried shunt in substantially inverse proportion to changes in the load resistance.

6. The combination with a constant potential source of alternating current, of a transformer comprising a magnetic core, pri- Ironary and secondary windings carried thereya ary magnetic shunt, a rectifier connected with said secondary windings, two windings connected respectively in shunt and in series with the load terminals and across said rectifier; said last named windings arranged to have opposing magnetic actions in said magnetic shunt whereby the permeability of the magnetic shunt is changed in substantially inverse proportion to changes in the load resistance.

7. The combination with a source of alternating current, of atransformer comprising a magnetic core, primary and secondary windings carried thereby, a source of direct current connected to be supplied by said secondary winding and windings on said core connected in series and in shunt with the load supplied by said source of direct current, and arranged to have a differential magnetizing efi'ect for changing the permeability of said core in substantially inverse proportion to changes in the load resistance.

In witness whereof I have hereunto set my hand this th day, of April, 1916.

THEODORE Bonn e.

said core being provided with a station-' 

